1.1a Particles in the atom and atomic radius

• Chemistry
• Secondary Education
• Age 12,13

AS Level Chemistry 9701

Topic 1.1 Particles in the atom and atomic radius

15 August 2023

My Goals Today

• explain that atoms are mostly empty space surrounding a very small, dense nucleus that contains protons and neutrons; electrons are found in shells in the empty space around the nucleus
• identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses
• define the terms atomic and proton number; mass and nucleon number
• describe the distribution of mass and charge within an atom
• describe the behaviour of beams of protons, neutrons and electrons moving at the same velocity in an electric field

My Goals Today

• determine the numbers of protons, neutrons and electrons present in both atoms and ions given atomic or proton number, mass or nucleon number and charge
• state and explain qualitatively the variations in atomic radius and ionic radius across a period and down a group
• define the term isotope in terms of numbers of protons and neutrons

Review of previous learning

• ⚗️ Atomic Structure Sketch (and model-making) 
• ⚗️ Advance video 1 viewing: Brief history of the atom in Moodle

Activity 1. The Atom (Classwork 1)

(Advanced video 1 watching)

• ⚗️ Video 1: about a brief history of atoms
• ⚗️ Answer the essential question: ❓How did the atom we know today develop from the past?
• ⚗️ Make a timeline at https://time.graphics/editor. 

Brief History of the Atom

• Democritus 
• John Dalton
• Michael Faraday
• J. J. Thomson
• Robert Millikan
• Ernest Rutherford
• Henry Mosely
• Niels Bohr
• Louis de Broglie and Schrödinger

Brief History of the Atom

• Democritus - "atomos"
• John Dalton - Dalton's Atomic Theory
• Michael Faraday - electric nature of the atomic structure
• J. J. Thomson - discovered electrons - Thomson’s Plum Pudding Model
• Robert Millikan - measured the charge of an electron using oil droplets
• Ernest Rutherford - Most of an atom is a space - Gold Foil Experiment

*1919- named positive charge the proton (+1)

*1932- Rutherford and James Chadwick discover neutron in the nucleus (no charge)

• Henry Mosely - Each element contains a unique number of protons. 
• Niels Bohr - Bohr’s Orbit Model
• Louis de Broglie and Schrödinger - Wave Mechanical Model

Activity 2. Rutherford's Gold Foil experiment

(Advanced video 2 watching)

• ⚗️ Discuss the relevance of watching the video and knowing how history relates to today's atomic structure.
• ⚗️ Processing of Video 2: Modern-day reconstruction of the historical experiment
• ⚗️ Essential question:❓What does the experiment tell you about the atomic structure?
• ⚗️Share your answers with the class.

Activity 2. Rutherford's Gold Foil experiment

Online Simulation 

• ⚗️ Navigate the simulation found at phet.colorado.edu/en/simulation/rutherford-scattering. 
• ⚗️ With your partner, write a one-sentence conclusion about the structure of the atom.
• ⚗️ Share your conclusion with the class.

The Subatomic Particles

The Subatomic Particles

Activity 3—The Subatomic Particles

Online Simulation 

• ⚗️ Navigate the simulation and build an atom at https://phet.colorado.edu/sims/html/build-an-atom/latest/build-an-atom_all.html. 
• ⚗️ With your partner, write a one-sentence conclusion about the location of the sub-atomic particles.
• ⚗️ Share your conclusion with the class.

Activity 4—Every Path Particles Take

Drawing / Sketching

• ⚗️ Draw, on a piece of paper, three lines for the subatomic particles' paths when the electric field is switched on.
• ⚗️ Share your output with the class.

Activity 4—Every Path Particles Take

(Advanced video 3 watching)

• ⚗️ Ask the essential question: ❓How does the video relate to the diagrams you created?
• ⚗️ Respond to the given essential question and share it with the class.